WTT Rigging & Lifting Operations 2 — Questions and Answers
Question 1: What is the ASME standard that governs the design, construction, and use of below-the-hook lifting devices used on wind turbine components?
- ASME B30.9
- ASME B30.20 (Correct answer)
- ASME B30.2
- ASME B30.10
Correct answer: ASME B30.20
ASME B30.20 specifically covers below-the-hook lifting devices, which include custom lifting beams, spreader bars, and other engineered attachments.
Question 2: When hoisting a wind turbine blade, what is the primary function of a tag line attached to the load?
- To support a portion of the blade's weight during the lift
- To control rotation and prevent the load from swinging into structures (Correct answer)
- To signal the crane operator when the load is in position
- To measure the distance between the load and the tower
Correct answer: To control rotation and prevent the load from swinging into structures
Tag lines are used to control load swing and rotation, keeping the suspended blade away from personnel and structures during the lift.
Question 3: What condition requires a synthetic web sling to be immediately removed from service?
- Minor surface abrasion with no fiber damage
- Discoloration from exposure to UV light
- Acid or caustic burns, melting, or charring of fibers (Correct answer)
- Mild soiling from grease or lubricant
Correct answer: Acid or caustic burns, melting, or charring of fibers
Chemical burns (acid/caustic) or thermal damage (melting, charring) compromise the structural integrity of synthetic fibers and require immediate removal from service.
Question 4: What is the purpose of using a corner saddle or edge protector when rigging with a synthetic sling over a structural beam?
- To increase the sling's WLL for the lift
- To protect the sling from cuts caused by sharp edges that could cause failure (Correct answer)
- To center the load automatically under the hook
- To prevent the sling from slipping along the beam
Correct answer: To protect the sling from cuts caused by sharp edges that could cause failure
Sharp corners and edges can cut into synthetic sling fibers, dramatically reducing load capacity, so edge protectors preserve sling integrity.
Question 5: What does the term 'de-rating' refer to when applied to rigging hardware?
- Increasing the WLL to account for a safety factor
- Reducing the WLL due to the angle, configuration, or condition of use (Correct answer)
- Removing old rigging from service after a set number of lifts
- Recertifying slings after inspection
Correct answer: Reducing the WLL due to the angle, configuration, or condition of use
De-rating reduces the effective WLL of rigging hardware to account for factors like sling angles, choker hitches, or wear that reduce safe capacity.
Question 6: What is the minimum D/d ratio typically required for a wire rope sling when it is bent around a pin or lifting point?
- 2:1
- 5:1 (Correct answer)
- 10:1
- 25:1
Correct answer: 5:1
Industry standards recommend a minimum D/d (bend diameter to rope diameter) ratio of 5:1 to prevent excessive stress on the wire rope fibers at the bend.
Question 7: What is the function of a load cell in a crane or rigging lifting operation?
- It stores electrical power for the crane's control system
- It measures the actual weight of the suspended load in real time (Correct answer)
- It controls the speed of the crane hoist drum
- It verifies the load's center of gravity before the lift begins
Correct answer: It measures the actual weight of the suspended load in real time
A load cell is a force-measuring instrument placed in line with the rigging that displays the actual dynamic load on the hook during the lift.
WTT Rigging & Lifting Operations 2
What is the ASME standard that governs the design, construction, and use of below-the-hook lifting devices used on wind turbine components?